Ion transport and selection through DCGC-based electroosmosis in a conducting nanofluidic channel

Abstract

Compared to conventional electroosmosis over a non-polarizable insulating surface with fixed surface charge (or zeta potential), induced-charge electroosmosis occurs over an electrically polarizable surface with the ability of surface charge modulation (both magnitude and sign) under externally applied electric fields. Here, for the first time we propose to extend the induced-charge electroosmosis to nanofluidic channels with conducting (ideally polarizable) walls. Furthermore, we present a numerical model to describe the electrokinetic transport in such conducting nanofluidic channels. The analysis of numerical results shows new applications of induced-charge electroosmosis for actively tunable ion selection and flexible flow control in nanofluidics. This is achieved through the direct contact gate control (DCGC) of surface charge in induced-charge electroosmosis by applying very low voltages directly on conducting walls of nanochannels.